


Conductor of Light

by burnttongueontea



Category: Harry Potter - J. K. Rowling, Sherlock (TV)
Genre: Gen, Hogwarts AU, Potter!Lock
Language: English
Status: In-Progress
Published: 2014-07-03
Updated: 2014-07-06
Packaged: 2018-02-07 08:31:03
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 4,064
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1892247
Author URL: https://archiveofourown.org/users/burnttongueontea/pseuds/burnttongueontea
Summary: <blockquote class="userstuff">
              <p>Professor McGonagall raised her eyes heavenward.<br/>"I knew you were going to do this, John," she said, despairingly. "A young man living alone and uncared for in a glorified broom cupboard? This is a school, for Merlin's sake. Somebody has to look after him. And nobody is willing to do it except the boy I most wish to see keeping his head down."<br/></p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> I have been wrestling with this fic alongside work and exams for months and I'm now on holiday and reasonably desperate to just start publishing it already. So I haven't really thought at all about accurate tags and all that stuff. It is a WiP but I have a good chunk written and a detailed plan, so, if the wind is with us, I should be able to update regularly til it's done. SHOULD.

At first, when John Watson heard crashing noises from the kitchen at five in the morning, he assumed his sister must be running away again.

He stayed in bed, barely even pausing in his reading. This had to be her fifth or sixth attempt, and he was tired of feeling like a prison warden. Let her go, he thought. _I’d_ leave, if I was her.

However, after a few minutes, it became obvious something much stranger was going on. The sound and smell of frying sausages began wafting up the stairs, creeping through the cracks around his bedroom door. Unable to imagine any satisfying explanation for this, John slipped a bookmark into his copy of _Strategic Defence in Duelling_ , put his socks on, and went to see what was happening.

“Harry?” he hissed, pushing open the kitchen door. She turned to him, startled. Wearing her favourite old grey pyjamas and pale, tired look, he wouldn’t have said she seemed out of the ordinary, except for the fact that she was standing over the hob, in the process of cooking a full English breakfast.

“You’re awake already?” she whispered back. “I was going to surprise you.”

John squinted at her.

“…what?”

“It’s today, right? The first of September?”

Of course it was. And they had firmly established traditions for this day: after a silent, tense family dinner the evening before, John would carefully fold everything into his trunk, make himself toast, and fuck off to King’s Cross before his older sister even woke up.

Something suspicious was definitely going on.

“Yes.”

“How are you feeling?”

“Are you… being _sisterly_?”

Harry smiled. It looked weird.

“Sit down! I’ll put the kettle on.”

Without smiling back, John went to the kitchen table and drew a chair out. There was a copy of the Quibbler on the table, a few days old, with a picture of a small yellow bear-like creature blinking dolefully on the front cover. A caption read, ‘ _Is The Future Of The Wheedlejim At Risk? Special Report, Page 5.’_

“So… how long have you been up?” asked Harry.

“A while.”

“I, um, heard you shouting. In the night.”

John froze, one hand on the magazine. He didn’t look up.

“Were you having a nightmare?”

Now he understood what this was. She sounded genuinely concerned. John could have laughed. Harry, concerned about him? Harry who kept everybody up at night worrying about what might happen to her, Harry whom he’d had to tread on eggshells around ever since her Hogwarts letter never came, Harry who spent every summer looking wounded when he walked into the room. Taking it upon herself to look after him and make him fried eggs.

He didn’t laugh.

“What’s it got to do with you?”

“I just wanted to make sure you were okay.”

“I’m fine. You know I’m fine. I’m going back to Hogwarts today.”

He brandished the fact like a shield: look, see? Still organised John, still clever John. I look after you; no need to start changing the natural order of things. He opened the Quibbler to page 5 and stared at the middle of the page, hoping to deter any further questions by seeming interested in the article.

 

_‘ … although Ministry officials are calling it a mystery, the cause of this reduction in numbers is no real secret. Woodland areas known to be inhabited by Wheedlejims, as well as other magical creatures like centaurs and unicorns, are increasingly being given over to Muggle developments, with no seeming regard for their value to the magical community, both human and wild. Many witches and wizards are now asking the question: why does the Ministry keep handing ownership to Muggle government?_

_“It’s well known that Ministry has more dealings with Muggle institutions than they openly admit to,” says Theodore Tattleton, leader of the SPW. “Recently there has been much speculation over a rumoured disagreement with the non-magical Prime Minister. We fear that important land is being used as nothing more than a bargaining chip in negotiations. Can we really afford to endanger our dwindling magical species?” ’_

Pretend as he might, the story was dry, and when Harry slid a plate laden with eggs, beans, sausage and toast towards him, he gave up. If he had been tempted to turn down the offer of a Sympathy Breakfast, the smell of it changed his mind, and he pulled it towards himself as she sat down in the chair opposite.

He began eating, waiting for her to start asking awkward questions. For a moment she seemed content to watch him in silence, but after a while, she said,

“Can I ask what the dream was about?”

He considered answering truthfully, but that would have led into conversations he didn't want to have. Besides, it was none of her business what he dreamed about.

“I had an exam, and I couldn’t answer any of the questions.”

“You’re a really shit liar.”

“Look, people have nightmares sometimes, Harry. It’s not that odd.”

“I know, but… you are. Odd, I mean. This summer, you’ve been odd.”

He shrugged, cutting a sausage in half.

“I think you’re imagining things.”

“I don’t think I am. John, I know we’re not that close, and I may be a Muggle, but - ”

“ _What_ did you just say _?_ ” John interrupted, horrified.

Harry didn’t flinch.

“I’m a Muggle,” she said again, flatly. “Don’t give me that look, I am, I’d rather be. I’m not embarrassed.”

“Yes, you are.” John tried and failed not to sound angry. “You’re letting them push you out. Don’t do that.”

She took this with a sullen expression. Then she said,

“So I'm not allowed to be one of you, but I'm not allowed to leave either. I can’t win, can I?”

“Harry, of course you're one of us. It’s not all about going to Hogwarts and making silly flashing lights.”

“Well, that’s easy for you to say.” She hesitated. “If I can't be a witch, surely I can at least be a part of this family. I was trying to be a good sister. Is that not allowed, either?”

“Of course it is. It's just a bit out of character, that's all.” He put down his knife and fork and pushed the chair back, deciding to leave before she could turn the conversation back to his nightmare. “Perfect eggs, though.”

She sat and watched him as he put his plate into the sink, where an enchanted scrubbing brush leapt promptly up to start cleaning it, and left the room.

 

* * *

 

 

Upstairs, before going back to finish the last bits of packing, he paused in front of the open door to his parents’ room. It looked all wrong for a bedroom at this time in the morning: the curtains were left open, and the bedlinen was neatly tucked and folded. Cold and unslept in.

“Where the Hell are you?” he hissed, to his parents’ empty bed. It didn’t reply. He knew the answer, anyway. Some work trip to the Philippines.

A framed photograph stood on the nightstand. It was too dim for him to see it properly but he knew the picture well; himself aged five and Harry aged seven, in Diagon Alley, posing excitedly with their tawny owl Una just moments after they had bought her. His only memory of that day was throwing a tantrum because Harry had gloated that, being the eldest, she would get to take Una to Hogwarts first. It felt like a very long time ago indeed.

John turned away and went into his own room. After pushing a treat through the bars of Una’s cage to distract her while he locked it, he went over to his desk and stared at the last unpacked items lying there. Things he had postponed thinking about because he didn’t know whether to take them or not.

A small, well-thumbed copy of _the Beginner’s Duelling Handbook_ , which he knew by heart, but might have felt incomplete without, went into his trunk. A Gryffindor tie with a large black potion-burn on the back, which he had hoped might just be concealed enough to get away with, went into the bin. And a pair of Ravenclaw-branded leather gloves which he had bought by mistake had the badges ripped off them, and were thrown into the trunk as a spare pair.

Finally, there was a piece of parchment, folded in half, with one word written on the front in untidy capitals: JOHN. Slowly, he picked it up, unfolded it, and looked at the message. His eyes scanned automatically from left to right, but he had read it so many times the words didn’t seem to mean anything anymore. Something for which he was overwhelmingly grateful.

Decisively, he put the short letter in the drawer and shut it. Then he worried about Harry prying into his room, and took it out again. Safer to keep it with him, as long as he tried not to think about it.

When he came back downstairs, his trunk thundering loudly down each step behind him, Harry was standing in the hallway with her arms folded, still looking unhappy.

“I have to ask you something.”

“What?”

She looked hesitant for a moment.

“You do like it there, don’t you? At Hogwarts?”

He frowned at her. “Course I like it.”

“I always just assumed you were having a great time. I realised I never actually asked.”

She was biting her lip. He read what was actually bothering her: the thought that maybe, just maybe, she’d been a bit selfish all these years.

“Has somebody cast a Personality-Changing Charm on you?”

“John…”

“You don’t _need_ to ask.  I’m fine. You know that,” he said, reassuringly.

“Okay.”

“Harry, for once, will you have a good year?”

“I’ll try.”

He put his trunk down and awkwardly extended his arms. Cautiously they embraced. Harry patted him on the back.

“Thanks for breakfast,” he said as they let go of one another. And then he left.


	2. Chapter 2

**Notes for the Chapter:**

> This chapter, honourable mention goes to my good friend Eve (wfftitwff.tumblr.com) for assisting me through the "writing this one sentence is making me want to beat my head against a wall" phase.  
> My thanks also to those who left kudos and subscribed. x

It was a grey, gloomy morning, and the little light that managed to filter into the station seemed to dull and darken the red paint on the Hogwarts Express. John dimly remembered feeling quite impressed by the sight of the scarlet steam engine the first time he had seen it, but today it looked tired and outdated, and that eleven-year-old boy felt like somebody from another life.

By arriving almost half an hour before departure, he had hoped to find a compartment to himself, but it looked like he was already beaten to it. A good number were already full of students chatting vigorously, or throwing Every-Flavour Beans at one another; most of the rest were occupied by lone sixth and seventh years who probably had a big enough sense of entitlement to tell you "actually, my friends are sitting in this compartment" if you tried anything.

He was immensely relieved, then, when he got to the back and saw that the very last compartment appeared empty. With a loud, satisfied sigh, he started hurrying to grab it before it was gone – only to realise that somebody else was already doing the same thing, a few steps ahead of him. A tall, dark-haired, thin-looking kid wearing plain unmarked robes, and pulling a very out-of-place Samsonite suitcase behind him.

The other boy caught sight of John and suddenly halted, just in front of the door.

“It’s alright, you can have it. You were here first,” John’s upbringing said before he gave it permission to do so.

“We can share it,” the boy replied, and immediately looked surprised, as if he had expected his mouth to say something entirely different.

For a moment they eyed one other warily, each boy trying to figure out what kind of person he had just agreed to share a very small space with. The boy had sharp, greyish eyes, and he didn’t seem at all ashamed about using them, giving John a long look that was both critical and curious. A different person might have felt embarrassed by the obvious visual investigation, but John took the opportunity to peer at his features and try and work out how old he was. It wasn’t obvious at all. His jaw and cheekbones had a strong structure, as if he was maturing towards adulthood – but he wore no house colours. The only other people on the platform without house colours were First Years.

Before the sizing-up was quite finished, unfortunately, a loud voice rang out behind them.

“Hey! You with the curly hair! You dropped your wand!”

An exasperated look came over the pale face.

“I suppose I can’t leave that behind,” he muttered. “Back in a moment.”

He left his suitcase on the platform and hurried off.

Alone, John turned to the challenge of getting his own luggage into the overhead rack. While there were advantages of owning a reliable dinosaur of a trunk that had been passed down through the family, there were also disadvantages, like the heavy wooden frame and utterly unnecessary size. He could probably have packed all his clothes, his sister and a small kayak in there. And while he wasn’t unfit by any stretch of the imagination, when it came down to it, he was a short boy with a large trunk. The laws of physics dictated that he was going to experience certain problems.

He leaned over and grappled with the case. He managed to get his arms around it, and shift it to about waist height, but then he lost his grip. The thing went right out of his hands, and he braced himself for the heavy thud of a trunk containing a year’s worth of his possessions hitting the floor. But it never came. Instead, his luggage came to a gentle halt in mid-air, and then rose smoothly upwards to slide itself neatly onto the shelf.

For a second John just stood staring at it. Then he heard a small cough from behind him, and realised his new acquaintance had reappeared in the door of the compartment. He was looking up at the trunk, but his gaze switched back to John soon enough, that same slightly-too-hard stare, although now there was something slightly sheepish in the way he twisted his lip at the same time.

“Was that you?” he asked, although he immediately realised it couldn’t have been. The boy was now safely reunited with his wand, but it was still in its box, not in his hand as it would have been if he’d just performed a spell. John noted this with some surprise. The boxes were redundant once the wand left the shop – John had never known any kid not to stow their first one protectively in their pocket the moment they walked out of Ollivander’s.

He was mistaken about the spell, though.

“Yes,” said the boy. John expected him to say something else, and he did look as if some explanation was on the tip of his tongue, but after a few moments of uncomfortable silence it became apparent that whatever it was, he had no intention of voicing it.

“Well, thanks,” John replied. He nodded, with a quick tight smile of acknowledgment, and turned away.

So he’d done it without his wand, then, unless he was lying. Surely that meant he couldn’t have done it on purpose, either. The last time John had used magic without his wand, he’d been ten, and having a fight with his sister. She’d been bald (and furious) for weeks. Could the sight of him dropping his trunk actually have triggered such a strong involuntary reaction? That would make him an unusually altruistic person. Out of the corner of his eye, he watched the other boy swing his suitcase overhead, trying to figure it out. He seemed more like a prickly, antisocial kid with a habit of staring too much.

 “I’m John, by the way,” he said suddenly. “John Watson. I don’t think I’ve seen you around – what year are you in?”

“Sherlock Holmes,” the boy answered,  avoiding eye contact. “You’re not obliged to make conversation with me. In fact, it might be better if you don’t.”

“No, I’d like to.”

That earned him Sherlock’s full attention, with an expression as concerned as if he’d just announced he enjoyed eating slugs. He looked intensely at John for a moment, and then replied to a question John had forgotten he’d asked.

“First year.”

“Really?” John raised his eyebrows. “You seem much older than you are.”

“I’m not eleven. I’m a late starter. Should be in fifth year.”

“My age, then.”

“Yes.” Sherlock turned back to the window, but he didn’t seem as determined to concentrate on the view of the platform as before. John followed his line of sight, and saw the station clock, which was showing exactly nine thirty. As if on cue, the train gave a little jolt, and they began pulling out of King’s Cross.

John drew breath in order to sigh sadly, but Sherlock did so himself before he got the chance, watching the train station gave way to a series of brick buildings flashing past in the drizzle. John blinked. Not that many people had cause to feel glum on the Hogwarts Express. Missing old friends, perhaps.

“Were you at a Muggle school before?” he ventured.

“No, I was privately tutored.”

“So why didn’t you come to Hogwarts?”

“I didn’t want to.”

“What?”

Sherlock glanced sideways at him, and spoke in an exasperated tone.

“Not everybody does, you know. It can’t be that great a shock.”

“No, no,” John corrected him hastily. “I didn’t mean that. _God_ no! I’m just surprised they would have let you stay home. If I thought I’d had a choice in the matter, I wouldn’t be here right now.”

He laughed uncertainly. Sherlock met his feeble joke with a cold expression.

“You don’t have a choice in the matter. I wasn’t the only one: my brother wanted me to stay at home.”

“And how come they listened to him?”

“He’s important,” Sherlock replied, as if this explained everything.

“So… why didn’t he want you to come?”

Sherlock’s eyes narrowed.

“Don’t you think you’re being intrusive?”

John smiled.

“Sorry. I’m only making small talk.”

“Oh, right. And if I was to ask you what’s bothering you such much that you haven’t slept properly in at least a week, would that be small talk, too? How about I ask why you’re avoiding your classmates when you clearly don’t suffer from social anxiety? Or maybe it’s just sibling issues you think are appropriate for discussion. If that’s the case, we can do a fair trade: I’ll explain my brother’s power complex and you can tell me all about your experience growing up with a Squib sister. Sound good?”

John’s mouth had dropped open.

“No, I didn’t think so,” said Sherlock curtly. “Like I said. Probably better if we don’t do conversation.”

He snapped his gaze back towards the window.

“Wait. Wait wait wait. You can’t just drop something like that and then stop talking to me. How did you know? I mean – alright, I guess I look tired, and I obviously wanted to sit on my own. But Harry. How did you know about her?”

“Do you really want me to answer that?” Sherlock asked, staring suspiciously at John.

“Of course!”

He cleared his throat.

“Well. You said I could have the empty compartment even though you were here first. At first that made me think you had a younger brother or sister, since older siblings are typically more generous because they grew up feeling responsible for making sure the younger child got fair shares. But on the other hand, the address tag on your trunk lists the names in your family as Andrew, Julie, Henrietta and John Watson of 46 Balham Road. Firstborn’s name always goes first, it’s convention. So, your sibling was in fact older than you, but all the same you took responsibility for her more often than vice versa. Then I just had to work out why that might be, which was reasonably obvious: that same trunk is obviously generations old, it has your surname engraved on the lock, suggesting that you come from a family with history of magic, but that your older sister doesn’t attend Hogwarts or she would have inherited it first. All of which made me think that she must be a Squib.”

“That’s… really impressive,” said John. He was grinning. He thought he might look like an idiot, but he kept on doing it.

“Is it? Not really. Basic. My brother’s been teaching me; he’s much better.”

Sherlock was smiling too, though, so John didn’t entirely buy into his self-deprecation.

“Teaching you? So there’s a method?”

“The science of deduction. I suppose you could call it a method, although I doubt you could master it.”

“Thanks,” snorted John.

“Oh, no need to be offended. Practically nobody can.”

They both stopped as the door of the compartment slid open, and the witch with the trolley smiled down at them both. “Anything to eat or drink, my dears?”

Sherlock watched John buy a chocolate frog with an expression of intrigue. When the witch had left John peered at the coins in his hand. “Wait… I think she undercharged me. Should I call her back?”

“It was on purpose,” said Sherlock promptly. “You reminded her of her dead son. And she thought you were being unnecessarily kind by talking to me.”

“Deductions again?” John asked. Sherlock nodded.

“Did you see the extra hand on her left ring finger, besides the ones for her engagement and marriage?”

He seemed much more relaxed now, replacing the reflex “leave-me-alone” with an almost puppyish eagerness to please.

“You think it was for a kid? How do you know it wasn’t an anniversary present, or something?” John probed.

“It was black. Nobody wears black to celebrate a marriage, nobody of her age, anyway.”

They went on discussing the trolley witch for some time, Sherlock making increasingly outlandish statements about her personal life, and John demanding proofs, culminating in the revelation that she was almost certainly having an ongoing affair with the driver of the Express. Then they lapsed into silence, as John finally got around to opening, and eating, his Frog.

“I guess you’re hoping to get sorted into Ravenclaw, then?” John asked through a mouthful of chocolate.

Sherlock gave him a puzzled look. “Sorry?”

John swallowed, and spoke more clearly.

“Ravenclaw?” No recognition appeared on Sherlock’s face. John shook his head. “Nobody’s told you anything, have they?”

“Apparently not,” Sherlock said bitterly, beginning to look tense once more. John hastened to reassure him.

“Well, there’s not that much to know about. Okay, there’s quite a lot, but it’s simple really. Basically, the school has a House system. The four Houses are Gryffindor, Ravenclaw, Slytherin and Hufflepuff. On the first evening of the school year, every new student gets called up to wear the Sorting Hat… which sort of reads your mind. And then places you in a House based on your personality. Gryffindor if you’re brave, Ravenclaw if you’re clever, Slytherin if you’re cunning, and Hufflepuff if you’re loyal. And then you stay in your House dormitory, play for your House team if you’re into sports, eat on your House table, et cetera… for the rest of the time you’re there. And there’s a competition every year, for which House gets the most points.”

Sherlock listened to this with a mildly bemused expression. When John had finished, he pushed his chin out for a moment, wearing a thinking frown.

“That is _ridiculous_ ,” he said.

John burst out laughing. “Yeah,” he said. “It is pretty stupid.”

“And nobody ever complains about this… bizarre segregation?”

“No. It’s Hogwarts. People love that kind of thing. You’re the first person I’ve ever met who even thought twice about it.”

“I’m horrified.”

John laughed again. “You probably should be. No, I won’t scare you - it’s alright, you’ll get used to it. I did.”

Sherlock didn’t seem  like he was going to reply at first. Instead he absent-mindedly picked up the dark blue box, opened it, and took out a long pale-ish wand, awkwardly holding it between finger and thumb. He appraised it for a moment, with the same expression of incredulity he had given for the House story, and then said without looking at John,

“I have the right not to get used to anything.”


End file.
